docs(guide): add guide for isOwner policy

Signed-off-by: Jim LAURIE <j.laurie6993@gmail.com>

docs/.vuepress/config.js

@@ -205,6 +205,7 @@ module.exports = {
             '/3.0.0-beta.x/guides/custom-data-response',
             '/3.0.0-beta.x/guides/custom-admin',
             '/3.0.0-beta.x/guides/client',
+            '/3.0.0-beta.x/guides/is-owner',
             '/3.0.0-beta.x/guides/draft',
             '/3.0.0-beta.x/guides/scheduled-publication',
             '/3.0.0-beta.x/guides/slug',

docs/3.0.0-beta.x/guides/is-owner.md

@@ -0,0 +1,128 @@
+# Create is owner policy
+
+This guide will explain how to create an update restriction for the entry's author only.
+
+## Introduction
+
+In many cases you would like that only the author of an entry has the ability to update or delete it's own entries.
+
+This is a feature that is requested many times and in this guide you will see how implement it by yourself.
+
+## Example
+
+For this example, we will need an Article Content Type.
+
+Add a `text` field and a `relation` field for this Content Type.
+
+The `relation` field is a **many-to-one** relation with User.<br>
+One User can have many Articles and one Article can have only one User.<br>
+Name the field `author` for the Article Content Type and `articles` on the User side.
+
+Now we are ready to start customization.
+
+## Apply the author by default
+
+When we are creating a new Article via `POST /articles` we would like to apply the authenticated user that execute the request as author of this article.
+
+To do that we will customize the `create` controller function of the Article API.
+
+**Concepts we will use:**
+Here is the code of [core controllers](../concepts/controllers.html#core-controllers).
+We will also use this [documentation](../plugins/users-permissions.html#user-object-in-strapi-context) to access the current authenticated user information.
+
+**Path —** `./api/article/controllers/Article.js`
+
+```js
+const { parseMultipartData, sanitizeEntity } = require('strapi-utils');
+
+module.exports = {
+  /**
+   * Create a record.
+   *
+   * @return {Object}
+   */
+
+  async create(ctx) {
+    let entity;
+    if (ctx.is('multipart')) {
+      const { data, files } = parseMultipartData(ctx);
+      data.author = ctx.state.user.id;
+      entity = await strapi.services.article.create(data, { files });
+    } else {
+      ctx.request.body.author = ctx.state.user.id;
+      entity = await strapi.services.article.create(ctx.request.body);
+    }
+    return sanitizeEntity(entity, { model: strapi.models.article });
+  },
+};
+```
+
+Now, when an article is created, the authenticated user is automaticaly set as author of the article.
+
+## Limit the update
+
+Now we will restrict the update of articles only for the author.
+
+We will use the same concepts as previously.
+
+**Path —** `./api/article/controllers/Article.js`
+
+```js
+const { parseMultipartData, sanitizeEntity } = require('strapi-utils');
+
+module.exports = {
+  /**
+   * Create a record.
+   *
+   * @return {Object}
+   */
+
+  async create(ctx) {
+    let entity;
+    if (ctx.is('multipart')) {
+      const { data, files } = parseMultipartData(ctx);
+      data.author = ctx.state.user.id;
+      entity = await strapi.services.article.create(data, { files });
+    } else {
+      ctx.request.body.author = ctx.state.user.id;
+      entity = await strapi.services.article.create(ctx.request.body);
+    }
+    return sanitizeEntity(entity, { model: strapi.models.article });
+  },
+
+  /**
+   * Update a record.
+   *
+   * @return {Object}
+   */
+
+  async update(ctx) {
+    let entity;
+
+    const [article] = await strapi.services.article.find({
+      id: ctx.params.id,
+      'author.id': ctx.state.user.id,
+    });
+
+    if (!article) {
+      return ctx.unauthorized(`You can't update this entry`);
+    }
+
+    if (ctx.is('multipart')) {
+      const { data, files } = parseMultipartData(ctx);
+      entity = await strapi.services.article.update(ctx.params, data, {
+        files,
+      });
+    } else {
+      entity = await strapi.services.article.update(
+        ctx.params,
+        ctx.request.body
+      );
+    }
+
+    return sanitizeEntity(entity, { model: strapi.models.article });
+  },
+};
+```
+
+And tada!